GE Hydran 201i, Instruction Manual

Page: 51 / 300

Battery
Part 17997 Rev. 6, March 2011 2-15
Temperatures are obtained through thermistors incorporated in the sensor body and the
heating plate. The heating plate power is controlled using a time-proportioning regulating
method. The proportional algorithm maintains the sensor temperature near the desired set
point, by modulating it with the dynamic oil sampling system. The heating plate
temperature is limited to 100 °C (212 °F); its variation rate is also controlled to avoid sensor
overheating.
Detection of an open thermistor shuts the heating power off. In addition, a thermostat
(item 11 in Figure 2-5 on page 2-9) with a 100 °C (212 °F) rating is located on the heating
plate to protect against any fault from the heating system.
2.7 BATTERY
The Hydran 201T i ’s battery is used to keep the real-time clock functioning and to retain the
parameter values and historic data when ac power is not available.
The battery is a lithium/manganese dioxide cell (1,000 mAh) with a service life of approx-
imately ten years, an extremely low self-discharge (1 % per year at 25 °C [77 °F]) and an
operating temperature range of 10 to 70 °C (50 to 158 °F). This type of battery is used in
critical conditions in the majority of military, industrial and commercial applications.
2.7.1 Estimated Life
A new battery delivers 3.0 V for about one half of its life and then its voltage starts
dropping.
Because the Hydran 201T i requires a minimum of 2.2 V, the set points of battery alarms
(see Service;Battery submenu in Section 4.5.4.3 on page 4-20) are adjusted to provide
warning delays of nine months (Low alarm = 2.75 V) and three months (Low-Low alarm
= 2.45 V) when operating at 60 °C (140 °F). These delays are doubled at 25 °C (77 °F).
The estimated battery life according to time is shown in Table 2-1 on page 2-16.
2.7.2 Disconnecting the Battery
It is recommended to disconnect the battery if the Hydran 201T i has to be stored for six
months or more.